Fuel dispensing nozzles are widely used and understood in the field. Early fuel nozzles are mainly comprised of a manual actuated valve and a metallic spout for directing fuel into a desired container. Many improvements have been made to fuel nozzles, including U.S. Pat. No. 4,453,578, which provide the means of automatically stopping fuel flow when the fuel reaches a desired level.
In addition, many design improvements have been made regarding nozzle spouts. U.S. Pat. No. 5,765,609 describes a method for manufacturing an aluminum spout that removably attaches to a nozzle body. Removable spouts enable them be replaced in shorter intervals than the more expensive nozzle body. Replacing a spout may be desirable when a nozzle is left in a motor vehicle after drive-away, upon considerable wear, or as improved spouts become available.
Recently, significant attention has been directed to the adverse environmental effects caused by fuel dispensing nozzles. One such effect is caused by fuel vapors displaced from a container as heavier liquid fuel is dispensed into the container. The displaced vapors contain volatile organics that chemically react with nitrogen oxides to form ground level ozone, often called “smog”. Ground level ozone can potentially cause irritation to the nose, throat, lungs and bring on asthma attacks. In addition, gasoline vapors are suspected to contain other harmful toxic chemicals, such as benzene.
In an effort to reduce the amount of harmful vapors that reach the atmosphere, a vapor recovery nozzle has been developed; one version of the spout is best described by U.S. Pat. No. 4,351,375. This version of a vapor recovery nozzle is comprised of a coaxial tube that both dispense fuel through a main tube and vacuum vapors through a secondary channel. A large percentage of the captured vapors are treated and safely released into the atmosphere. Vapor recovery systems are required by the laws of many states, especially at high volume stations or stations located in densely populated areas. California's Air Resource Board (CARB) is largely responsible for setting forth new standards for fuel dispensing nozzles.
Although vapor recovery has significantly reduced the amount of volatile organics that reach the atmosphere during fueling, there are several other sources of fuel vapors that contribute to the problem of “smog”. One such source is fuel dripped from a nozzle spout after fueling. Typically, when a nozzle is deactivated there is a delay before the user removes the nozzle spout from the container to be filled. If the delay is sufficient, drops from the spout will fall into the container. If the delay is insufficient, drops fall onto the ground or the local filling equipment. Spilt fuel evaporates into the atmosphere and contaminates the ground. Even waiting a significant amount of time before removing the nozzle will not ensure that dripping will not occur. Some users try to supplement waiting by tapping the nozzle spout on the fill tube of the container prior to removing it.
In an effort to further reduce sources of “smog” many new nozzle requirements and laws have been implemented. One such requirement is for fuel nozzles to be dripless. The goal is to have zero drops fall from a nozzle spout after the flow has stopped and a reasonable amount of time has elapsed. Many new nozzle designs are directed towards the goal of dripless, such as U.S. Pat. No. 6,520,222, U.S. Pat. No. 5,603,364, U.S. Pat. No. 4,213,488, U.S. Pat. No. 5,645,116, and U.S. Pat. No. 5,620,032. Although the aforementioned patents may potentially serve in the direction of their intended purposes, most are unlikely to reliably provide true dripless performance. Many proposed dripless nozzles continue to drip fuel long after the period of time it takes for a user to remove a spout from a tank.
In these respects, the low surface energy dripless fuel dispensing nozzle spout according to the present invention substantially departs from conventional concepts of the prior art, and in doing so provides an apparatus primarily designed for the purpose of reducing the amount of vapor that reaches the atmosphere during a fueling cycle.